Bobbin-case and hook for sewing-machines.



]. LEATHEM.

BOBBIN CASE AND HOOK FOB SEWING MACHINES.

APPLICATION FILED MAY 4. 1914.

Patented-F61). 5,1918;-

irn eras rarian t 00., OF NEW YORK, N.

1., A CORPORATION OF NEW YORK.

BOBBIN-GASE AND HOOK FOR, SEVVING-MACHINES.

Specification of Letters Patent.

Patented Feb, 5, 191%..

Application filed May 4c, 1914;. seriainoissalw To all whom it may concern Be itknown that I, Janus LEATHEM, a citizen of the United States, and a resident of Lebanon, in the county of Lebanon and State of Pennsylvania, have invented certain new and useful Improvements in Bobbin-Cases and Hooks for Sewing-h lachines, of which the following is a specification.

My invention relates to sewing machines, and particularly to a bobbin case for rotary hook sewing machines having improved means for engaging one side of the loop of needle thread, also the combination, with the bobbin case having such improved means for engaging the loop of needle thread, of a rotary hook having its beak positioned to co operate to best advantage with such needlethread-engagii'lg means of the bobbin case. My invention consists in the bobbin case having the improved needle thread-engaging means herein described and in the combination with such bobbin case of a rotary hook having its beak arranged as herein described.

The object of my invention is to improve sewing machines, particularly the lock stitch mechanism thereof.

I will now proceed to describe my invention with reference to the accompanying drawings, and will then point out the novel features in claims.

Figure 1 shows a top view of a hook and bobbin case embodying my invention, the bobbin being shown in place within the bobbin case;

Fig. 2 shows a side elevation of the same parts;

Fig. 3 shows a top view and partial horizontal section of the bobbin case, the bobbin having been removed, and

Fig. l shows a side elevation of the bobbin case.

In the'drawings, 1 designates the rotary so-called hook or loop-taker of a lock stitch sewing machine mechanism, 2 desig nates the thread slot of such hook, and 3 designates the beak of such hook. l designates the bobbin case, and 5 the bobbin therein. The hook, bobbin case, and bobbin are of the general construction set forth in my Patent No. 1,099,655. dated June 9, 1914, and in my prior application for Letters Patent Serial September 3, 1913, except in the respects hereinafter noted; and I have shown the No. 788,012 and bobbin case as provided with a tension device 6 for the bobbin thread, which tension device is ofthe construction illustrated and described in my companion application for Letters Patent filed May l, 1914, Serial No. 836,166. But I do not limit myself to the use of that or any particular tension device, and

so do not particularly describe such tension device herein. 7

As means for engaging one side of the loop of needle'thread, the bobbin case is provided at a point preferably approximately midway between its base and its supporting flange 7 with a short laterally projecting lug S, the outer surface of whichlug is beveled downwardly and inwardly (i. c., toward the axis of the bobbin case) as indicated particularly in Fig. i l. The narrow lug 8 is also beveled downwardly and inwardly so as to prevent the thread, as much as possible from being broken by being squeezed against the inner side of the hook. It will be observed with reference to Fig. 2 that the point of the beak 3 of the hook is depressed slightly above the plane of the lug 8; such position of the beak I have found to be most advantageous for cooperation with needle-thread-engaging means such as the lug 8.

The bobbin case is provided with the usual lug 10 adapted for engagement with a fixed part of the sewing machine, whereby rotation of the bobbincase is prevented.

As is well known the action of a hook and bobbin case, such as described in relation to the needle thread or top thread, is as follows: During the rotation of the hook or loop-taker 1, the beak 3 passes through a bight or loop of the needle thread or top thread; and continued rotation of the looptaker carries one side of the bight of such needle thread down to the base of thread slot 2. As the loop-taker 1 continues to rotate the needle thread passes underneath the bobbin case and then pulls off the beak. It is desirable that one side of the bight of the needle thread shall be engaged by the bobbin case and held, otherwise both sides of the bight of needle thread might be carried around the bobbin case without passing underneath the bobbin case, and so without interlocking with the bobbin thread. In the present construction, the lug 8, projecting from the bobbin case, performs this function of engaging one side of the loop of later sion of such lugs (corresponding to the succession of notches in the side of the bobbin case illustrated in my Patent No. 1,099,655) the one lug 8 being always effective, as

stated. For this reason the stitching is par ticularly uniform, Depression of thepoint of the beak '3 into close proximity to this lug S is also important, as by reason of such depression of the beak the engagement of the loop and'needle thread by the pin 8 is rendered the more certain.

What I claim is: 1. A bobbin case for rotary hook sewing machines having needle thread engaging means comprising a laterally projecting cyly'ndrical lug spaced away from the 'top' of said case.

2.- A bobbin case for rotary hook sewing machines having needle thread engaging means comprising a narrow laterally projecting lug, beveled downwardly and inwardly secured to the side of said case below the top thereof.

3. The combination with a bobbin case provided with a pin shaped lug projecting laterally from the side of said case and spaced away from the top thereof, the outer face of said lug being inclined, said lug being adapted to engage a loop of needle thread of a rotary hook within which said bobbin case is located, said hook having the point of its beak located in proximity to such lug.-

4 The combination with a bobbin case provided with a needle-thread-engagn'ng means comprising a pin-shaped lug projecting laterally from the side of the bobbin case at a point well below the top of such bobbin case, of a rotary hook within which such bobbin case is located, said hook having the point of its beak depressed, below the top of the hook, to a point in close proximity to the plane of such lug.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

JAMES LEATIIEM.

Vitnesses:

J. W. Ross, MARY R. Ross.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

